Abstract
We develop an explicitly time-dependent theory for one-step resonant excitation-deexcitation processes of core electron states in diatomic molecules. Emphasis is placed on a conceptual picture demonstrating how the effective time of the formation of the spectra—which is influenced by the bandwidth of the exciting radiation, by the excitation of the molecule being resonant or off resonant (detuned), and by the actual core hole lifetime—changes the appearance of the deexcitation electron spectra. Explicit time-dependent model calculations for three final states each of [Formula Presented]-hole excited [Formula Presented] (including one spectator decay) and [Formula Presented]–hole excited CO allow demonstration of the various consequences for the spectral shapes which derive from these influences. In particular, off-resonance excitation is shown to shorten the effective time of the spectrum formation below the lifetime of the core-excited state leading to the recently observed collapse of the vibrational structure in the spectrum. Our calculated spectra also demonstrate the influences of the relative positions and shapes of the potential curves involved. On resonance, the nodal structure of the vibrational wave functions of the core-excited state is reflected in the shapes of the spectator decay spectra of [Formula Presented] with a soft final state interatomic potential.
Original language | English |
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Pages (from-to) | 1225-1246 |
Number of pages | 22 |
Journal | Physical Review A |
Volume | 58 |
Issue number | 2 |
DOIs | |
State | Published - 1998 |